A recent study reports that nitrate-rich vegetables, such as beats and leafy greens, can reduce the risk of heart attacks and strokes.
Vegetables are considered by many to be a healthy part of a daily diet. This general rule has been validated in the medical community by scientific research that shows a connection between a vegetable rich diet and improved cardiovascular health. Atherosclerotic vascular disease (ASVD), or atherosclerosis is among the leading causes of death in the modern population. Initial warning signs of atherosclerosis include elevated cholesterol levels, arterial plaque formation, and endothelial dysfunction – the inability of blood vessels to regulate vasodilation and vasoconstriction. These factors restrict blood flow along the arteries, and can lead to death-causing heart attacks and strokes. Due to the high occurrence of atherosclerosis in today’s world, there is a growing need to develop strategies that stop this disease from escalating into deadly conditions.
Nitric oxide (NO) is an important stimulator of vasodilation, but the cellular pathways that generate NO break down as atherosclerosis progresses. This is where vegetables play a cardioprotective role. Some vegetables are excellent sources of nitrates, which are readily used by the body as an alternative way of synthesizing NO. This additional NO improves endothelial function and lowers blood pressure by restoring the mechanisms that regulate blood vessel dilation. However, despite these outcomes it was not clear whether this additional NO was sufficient to prevent atherosclerosis induced mortality. Researchers from the University of Western Australia looked further into this question and found evidence that a diet rich in high nitrate vegetables is inversely correlated with atherosclerosis related mortality. Their findings were published in the American Journal of Clinical Nutrition earlier this year.
This study monitored the diet patterns of 1226 Australian women over 15 years and looked for a correlation between diet and instances of atherosclerosis-related causes of death. Atherosclerosis-related causes of death included death from ischemic heart disease, heart failure, and cerebrovascular disease. At the beginning of the study, all participants were between 70 and 85 years of age, and all were clear of atherosclerosis. The dietary habits of all participants were assessed using self-administered food-frequency questionnaires, and then analyzed with the NUTTAB95 food nutrient database to determine the nutritional content of the food consumed by each participant. The nitrate content consumed by each participant was calculated by multiplying the weight of vegetables consumed per day (g) by the median nitrate value (mg/g) reported for that vegetable in a published database. Nitrate values obtained from other food sources were calculated in a similar manner. Physical activity levels, alcohol use, smoking history and the medical history of each individual were accounted for using a questionnaire.
At the end of the 15 year analysis, 238 out of 1226 women (19.4%) died of atherosclerosis related diseases. Even after researchers accounted for other factors that influence atherosclerosis-related death, such as different lifestyles, fitness levels, and disease susceptibilities of the patients, they still found that consumption of nitrate rich vegetables inversely correlated with atherosclerosis related death, and was associated with a lower overall mortality rate. Despite the fact that there are many different factors that influence atherosclerosis disease progression, this study provides evidence of a link between the nitrate content obtained from vegetables and cardiovascular mortality. It would be interesting to expand on this research to investigate whether patients at risk of atherosclerosis related cardiovascular attacks might enjoy longer lifespans by increasing the amount of nitrate-rich vegetables in their diet.
Written By: Irina Sementchoukova, B.Sc